The capacitor utilized for central processing unit (CPU) for personal computers and the like is required to have high capacitance and low ESR (equivalent series resistance) so as to suppress the fluctuation of voltage and reduce the heat generation at the passing of a high ripple current.
Generally, an aluminum or tantalum solid electrolytic capacitor is used.
The solid electrolytic capacitor is produced by stacking a dielectric layer on a surface of an anode body comprising a valve-acting metal or an electrically conducting oxide, further sequentially stacking a semiconductor layer and an electrically conducting layer on the dielectric layer to prepare a solid electrolytic capacitor element, and molding it with a jacket material. As for the shape of the anode body, a metal foil or electrically conducting oxide foil having fine pores in the surface layer and a metal powder or electrically conducting powder sintered body having fine pores in the inside are known. The dielectric layer is formed also on the surface of such a fine pore of the anode body, and the semiconductor layer is stacked also on the dielectric layer within the pore. A solid electrolytic capacitor with low ESR is produced by using an organic or inorganic semiconductor having a high electric conductivity for the semiconductor layer.
Also, studies are being made to produce a solid electrolytic capacitor with low ESR by improving the electrically conducting paste used for forming the electrically conducting layer of the solid electrolytic capacitor. For example, JP-A-2003-059338 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”) discloses a composition comprising two components of carbon powder and electrically conducting metal powder and JP-A-2003-203828 discloses an electrically conducting polymer layer for connecting electrically conducting metal particles of the electrically conducting paste layer.